“What is the value of a human life?” is a notoriously difficult question, probably because people keep trying to answer it in terms of dollars, and it rightfully offends our moral sensibilities to do so. We shouldn’t be valuing people in terms of dollars—we should be valuing dollars in terms of their benefits to people.

So let me ask a simpler question: Does the value of an individual human life increase, decrease, or stay the same, as we increase the number of people in the world?

A case can be made that it should stay the same: Why should my value as a person depend upon how many other people there are? Everything that I am, I still am, whether there are a billion other people or a thousand.

But in fact I think the correct answer is that it decreases. This is for two reasons: First, anything that I can do is less valuable if there are other people who can do it better. This is true whether we’re talking about writing blog posts or ending world hunger. Second, and most importantly, if the number of humans in the world gets small enough, we begin to face danger of total permanent extinction.

If the value of a human life is constant, then 1,000 deaths is equally bad whether it happens in a population of 10,000 or a population of 10 billion. That doesn’t seem right, does it? It seems more reasonable to say that losing ten percent should have a roughly constant effect; in that case losing 1,000 people in a population of 10,000 is equally bad as losing 1 billion in a population of 10 billion. If that seems too strong, we could choose some value in between, and say perhaps that losing 1,000 out of 10,000 is equally bad as losing 1 million out of 1 billion. This would mean that the value of 1 person’s life today is about 1/1,000 of what it was immediately after the Toba Event.

Of course, with such uncertainty, perhaps it’s safest to assume constant value. This seems the fairest, and it is certainly a reasonable approximation.

In any case, I think it should be obvious that the inherent value of a human life does not increase as you add more human lives. Losing 1,000 people out of a population of 7 billion is not worse than losing 1,000 people out of a population of 10,000. That way lies nonsense.

Yet if we agree that the value of a human life is not increasing, this has a very important counter-intuitive consequence: It means that increasing the risk of a global catastrophe is at least as bad as causing a proportional number of deaths. Specifically, it implies that a 1% risk of global nuclear war is worse than killing 10 million people outright.

The calculation is simple: If the value of a human life is a constant V, then the expected utility (admittedly, expected utility theory has its flaws) from killing 10 million people is -10 million V. But the expected utility from a 1% risk of global nuclear war is 1% times -V times the expected number of deaths from such a nuclear war—and I think even 2 billion is a conservative estimate. (0.01)(-2 billion) V = -20 million V.

This probably sounds too abstract, or even cold, so let me put it another way. Suppose we had the choice between two worlds, and these were the only worlds we could choose from. In world A, there are 100 leaders who each make choices that result in 10 million deaths. In world B, there are 100 leaders who each make choices that result in a 1% chance of nuclear war. Which world should we choose?

The choice is a terrible one, to be sure.

In world A, 1 billion people die.

Yet what happens in world B?

If the risks are independent, we can’t just multiply by 100 to get a guarantee of nuclear war. The actual probability is 1-(1-0.01)^100 = 63%. Yet even so, (0.63)(2 billion) = 1.26 billion. The expected number of deaths is higher in world B. Indeed, the most likely scenario is that 2 billion people die.

Yet this is probably too conservative. The risks are most likely positively correlated; two world leaders who each take a 1% chance of nuclear war probably do so in response to one another. Therefore maybe adding up the chances isn’t actually so unreasonable—for all practical intents and purposes, we may be best off considering nuclear war in world B as guaranteed to happen. In that case, world B is even worse.

What does this imply for global policy? It means that we should be far more aggressive in punishing any action that seems to bring the world closer to nuclear war. Even tinyincreases in risk, of the sort that would ordinarily be considered negligible, are as bad as murder. A measurably large increase is as bad as genocide.

Of course, in practice, we have to be able to measure something in order to punish it. We can’t have politicians imprisoned over 0.000001% chances of nuclear war, because such a chance is so tiny that there would be no way to attain even reasonable certainty that such a change had even occurred, much less who was responsible.

Even for very large chances—and in this context, 1% is very large—it would be highly problematic to directly penalize increasing the probability, as we have no consistent, fair, objective measure of that probability.

Therefore in practice what I think we must do is severely and mercilessly penalize certain types of actions that would be reasonably expected to increase the probability of catastrophic nuclear war.

If we had the chance to start over from the Manhattan Project, maybe simply building a nuclear weapon should be considered a war crime. But at this point, nuclear proliferation has already proceeded far enough that this is no longer a viable option. At least the US and Russia for the time being seem poised to maintain their nuclear arsenals, and in fact it’s probably better for them to keep maintaining and updating them rather than leaving decades-old ICBMs to rot.

What can we do instead?

First, we probably need to penalize speech that would tend to incite war between nuclear powers. Normally I am fiercely opposed to restrictions on speech, but this is nuclear war we’re talking about. We can’t take any chances on this one. If there is even a slight chance that a leader’s rhetoric might trigger a nuclear conflict, they should be censored, punished, and probably even imprisoned. Making even a veiled threat of nuclear war is like pointing a gun at someone’s head and threatening to shoot them—only the gun is pointed at everyone’s head simultaneously. This isn’t just yelling “fire” in a crowded theater; it’s literally threatening to burn down every theater in the world at once.

Such a regulation must be designed to allow speech that is necessary for diplomatic negotiations, as conflicts will invariably arise between any two countries. We need to find a way to draw the line so that it’s possible for a US President to criticize Russia’s intervention in the Ukraine or for a Chinese President to challenge US trade policy, without being accused of inciting war between nuclear powers. But one thing is quite clear: Wherever we draw that line, President Trump’s statement about “fire and fury” definitely crosses it. This is a direct threat of nuclear war, and it should be considered a war crime. That reason by itself—let alone his web of Russian entanglements and violations of the Emoluments Clause—should be sufficient to not only have Trump removed from office, but to have him tried at the Hague. Impulsiveness and incompetence are no excuse when weapons of mass destruction are involved.

Second, any nuclear policy that would tend to increase first-strike capability rather than second-strike capability should be considered a violation of international law. In case you are unfamiliar with such terms: First-strike capability consists of weapons such as ICBMs that are only viable to use as the opening salvo of an attack, because their launch sites can be easily located and targeted. Second-strike capability consists of weapons such as submarines that are more concealable, so it’s much more likely that they could wait for an attack to happen, confirm who was responsible and how much damage was done, and then retaliate afterward.
Even that retaliation would be difficult to justify: It’s effectively answering genocide with genocide, the ultimate expression of “an eye for an eye” writ large upon humanity’s future. I’ve previously written about my Credible Targeted Conventional Response strategy that makes it both more ethical and more credible to respond to a nuclear attack with a non-nuclear retaliation. But at least second-strike weapons are not inherently only functional at starting a nuclear war. A first-strike weapon can theoretically be fired in response to a surprise attack, but only before the attack hits you—which gives you literally minutes to decide the fate of the world, most likely with only the sketchiest of information upon which to base your decision. Second-strike weapons allow deliberation. They give us a chance to think carefully for a moment before we unleash irrevocable devastation.

All the launch codes should of course be randomized onetime pads for utmost security. But in addition to the launch codes themselves, I believe that anyone who wants to launch a nuclear weapon should be required to type, letter by letter (no copy-pasting), and then have the machine read aloud, Oppenheimer’s line about Shiva, “Now I am become Death, the destroyer of worlds.” Perhaps the passphrase should conclude with something like “I hereby sentence millions of innocent children to death by fire, and millions more to death by cancer.” I want it to be as salient as possible in the heads of every single soldier and technician just exactly how many innocent people they are killing. And if that means they won’t turn the key—so be it. (Indeed, I wouldn’t mind if every Hellfire missile required a passphrase of “By the authority vested in me by the United States of America, I hereby sentence you to death or dismemberment.” Somehow I think our drone strike numbers might go down. And don’t tell me they couldn’t; this isn’t like shooting a rifle in a firefight. These strikes are planned days in advance and specifically designed to be unpredictable by their targets.)

If everyone is going to have guns pointed at each other, at least in a second-strike world they’re wearing body armor and the first one to pull the trigger won’t automatically be the last one left standing.

Third, nuclear non-proliferation treaties need to be strengthened into disarmament treaties, with rapid but achievable timelines for disarmament of all nuclear weapons, starting with the nations that have the largest arsenals. Random inspections of the disarmament should be performed without warning on a frequent schedule. Any nation that is so much as a day late on their disarmament deadlines needs to have its leaders likewise hauled off to the Hague. If there is any doubt at all in your mind whether your government will meet its deadlines, you need to double your disarmament budget. And if your government is too corrupt or too bureaucratic to meet its deadlines even if they try, well, you’d better shape up fast. We’ll keep removing and imprisoning your leaders until you do. Once again, nothing can be left to chance.

We might want to maintain some small nuclear arsenal for the sole purpose of deflecting asteroids from colliding with the Earth. If so, that arsenal should be jointly owned and frequently inspected by both the United States and Russia—not just the nuclear superpowers, but also the only two nations with sufficient rocket launch capability in any case. The launch of the deflection missiles should require joint authorization from the presidents of both nations. But in fact nuclear weapons are probably not necessary for such a deflection; nuclear rockets would probably be a better option. Vaporizing the asteroid wouldn’t accomplish much, even if you could do it; what you actually want to do is impart as much sideways momentum as possible.

What I’m saying probably sounds extreme. It may even seem unjust or irrational. But look at those numbers again. Think carefully about the value of a human life. When we are talking about a risk of total human extinction, this is what rationality looks like. Zero tolerance for drug abuse or even terrorism is a ridiculous policy that does more harm than good. Zero tolerance for risk of nuclear war may be the only hope for humanity’s ongoing survival.

Throughout the vastness of the universe, there are probably billions of civilizations—I need only assume one civilization for every hundred galaxies. Of the civilizations that were unwilling to adopt zero tolerance policies on weapons of mass destruction and bear any cost, however unthinkable, to prevent their own extinction, there is almost boundless diversity, but they all have one thing in common: None of them will exist much longer. The only civilizations that last are the ones that refuse to tolerate weapons of mass destruction.

One of the most plausible solutions to the Fermi Paradox of why we have not found any other intelligent life in the universe is called the Great Filter: Somewhere in the process of evolving from unicellular prokaryotes to becoming an interstellar civilization, there is some highly-probable event that breaks the process, a “filter” that screens out all but the luckiest species—or perhaps literally all of them.

Yet there is a deep reason why we would expect that this is precisely the combination that would emerge in most species (as it has certainly emerged in our own): The rationality of a species is not uniform. Some individuals in a species will always be more rational than others, so as a species increases its level of rationality, it does not do so all at once.

Indeed, the processes of economic development and scientific advancement that make a species more rational are unlikely to be spread evenly; some cultures will develop faster than others, and some individuals within a given culture will be further along than others. While the mean level of rationality increases, the variance will also tend to increase.

On some arbitrary and oversimplified scale where 1 is the level of rationality needed to maintain a hunter-gatherer tribe, and 20 is the level of rationality needed to invent nuclear weapons, the distribution of rationality in a population starts something like this:

Most of the population is between levels 1 and 3, which we might think of as lying between the bare minimum for a tribe to survive and the level at which one can start to make advances in knowledge and culture.

Then, as the society advances, it goes through a phase like this:

This is about where we were in Periclean Athens. Most of the population is between levels 2 and 8. Level 2 used to be the average level of rationality back when we were hunter-gatherers. Level 8 is the level of philosophers like Archimedes and Pythagoras.

Today, our society looks like this:

Most of the society is between levels 4 and 20. As I said, level 20 is the point at which it becomes feasible to develop nuclear weapons. Some of the world’s people are extremely intelligent and rational, and almost everyone is more rational than even the smartest people in hunter-gatherer times, but now there is enormous variation.

Where on this chart are racism and nationalism? Importantly, I think they are above the level of rationality that most people had in ancient times. Even Greek philosophers had attitudes toward slaves and other cultures that the modern KKK would find repulsive. I think on this scale racism is about a 10 and nationalism is about a 12.

If we had managed to uniformly increase the rationality of our society, with everyone gaining at the same rate, our distribution would instead look like this:

If that were the case, we’d be fine. The lowest level of rationality widespread in the population would be 14, which is already beyond racism and nationalism. (Maybe it’s about the level of humanities professors today? That makes them substantially below quantum physicists who are 20 by construction… but hey, still almost twice as good as the Greek philosophers they revere.) We would have our nuclear technology, but it would not endanger our future—we wouldn’t even use it for weapons, we’d use it for power generation and space travel. Indeed, this lower-variance high-rationality state seems to be about what they have the Star Trek universe.

But since we didn’t, a large chunk of our population is between 10 and 12—that is, still racist or nationalist. We have the nuclear weapons, and we have people who might actually be willing to use them.

I think this is what happens to most advanced civilizations around the galaxy. By the time they invent space travel, they have also invented nuclear weapons—but they still have their equivalent of racism and nationalism. And most of the time, the two combine into a volatile mix that results in the destruction or regression of their entire civilization.

If this is right, then we may be living at the most important moment in human history. It may be right here, right now, that we have the only chance we’ll ever get to turn the tide. We have to find a way to reduce the variance, to raise the rest of the world’s population past nationalism to a cosmopolitan morality. And we may have very little time.

This post will have two parts, corresponding to each sentence. First, I hope to convince you that nuclear power is safe. Second, I’ll try to analyze some of the reasons why people don’t like it and what we might be able to do about that.

Depending on how familiar you are with the statistics on nuclear power, the idea that nuclear power is safe may strike you as either a completely ridiculous claim or an egregious understatement. If your primary familiarity with nuclear power safety is via the widely-publicized examples of Chernobyl, Three Mile Island, and more recently Fukushima, you may have the impression that nuclear power carries huge, catastrophic risks. (You may also be confusing nuclear power with nuclear weapons—nuclear weaponsare indeed the greatest catastrophic risk on Earth today, but equating the two is like equating automobiles and machine guns because both of them are made of metal and contain lubricant, flammable materials, and springs.)

But in fact nuclear energy is astonishingly safe. Indeed, even those examples aren’t nearly as bad as people have been led to believe. Guess how many people died as a result of Three Mile Island, including estimated increased cancer deaths from radiation exposure?

I also haven’t included deaths due to pollution—note that nuclear power plants don’t pollute air or water whatsoever, and only produce very small amounts of waste that can be quite safely stored. Air pollution in all its forms is responsible for one in eight deaths worldwide. Let me say that again: One in eight of all deaths in the world is caused by air pollution—so this is on the order of 7 million deaths per year, every year. We burn our way to a biannual Holocaust. Most of this pollution is actually caused by burning wood—fireplaces, wood stoves, and bonfires are terrible for the air—and many countries would actually see a substantial reduction in their toxic pollution if they switched to oil or even coal in favor of wood. But a large part of that pollution is caused by coal, and a nontrivial amount is caused by oil. Coal-burning factories and power plants are responsible for about 1 million deaths per year in China alone. Most of that pollution could be prevented if those power plants were nuclear instead.

Factor all that in, and nuclear power currently saves tens if not hundreds of thousands of lives per year, and expanding it to replace all fossil fuels could save millions more. Indeed, a more precise estimate of the benefits of nuclear power published a few years ago in Environmental Science and Technologyis that nuclear power plants have saved some 1.8 million human lives since their invention, putting them on a par with penicillin and the polio vaccine.

So, I hope I’ve convinced you of the first proposition: Nuclear power plants are safe—and not just safe, but heroic, in fact one of the greatest life-saving technologies ever invented. So, why don’t people like them?

Unfortunately, I suspect that no amount of statistical data by itself will convince those who still feel a deep-seated revulsion to nuclear power. Even many environmentalists, people who could be nuclear energy’s greatest advocates, are often opposed to it. I read all the way through Naomi Klein’s This Changes Everythingand never found even a single cogent argument against nuclear power; she simply takes it as obvious that nuclear power is “more of the same line of thinking that got us in this mess”. Perhaps because nuclear power could be enormously profitable for certain corporations (which is true; but then, it’s also true of solar and wind power)? Or because it also fits this narrative of “raping and despoiling the Earth” (sort of, I guess)? She never really does explain; I’m guessing she assumes that her audience will simply share her “gut feeling” intuition that nuclear power is dangerous and untrustworthy. One of the most important inconvenient truths for environmentalists is that nuclear power is not only safe, it is almost certainly our best hope for stopping climate change.

Perhaps all this is less baffling when we recognize that other heroic technologies are often also feared or despised for similarly bizarre reasons—vaccines, for instance.

First of all, human beings fear what we cannot understand, and while the human immune system is certainly immensely complicated, nuclear power is based on quantum mechanics, a realm of scientific knowledge so difficult and esoteric that it is frequently used as the paradigm example of something that is hard to understand. (As Feynman famously said, “I think I can safely say that nobody understands quantum mechanics.”) Nor does it help that popular treatments of quantum physics typically bear about as much resemblance to the actual content of the theory as the X-Men films do to evolutionary biology, and con artists like Deepak Chopra take advantage of this confusion to peddle their quackery.

Vividness makes ideas more available to our memory; and thus, by the availability heuristic, we automatically infer that it must be more probable than it truly is. You can think of horrific nuclear accidents like Chernobyl, and all the carnage they caused; but all those millions of people choking to death in China don’t make for a compelling TV news segment (or at least, our TV news doesn’t seem to think so). Vividness doesn’t actually seem to make things more persuasive, but it does make them more memorable.

Yet even if we allow for the possibility that death by radiation poisoning is somewhat worse than death by coal pollution (if I had to choose between the two, okay, maybe I’d go with the coal), surely it’s not ten thousand times worse? Surely it’s not worth sacrificing entire cities full of people to coal in order to prevent a handful of deaths by nuclear energy?

Another reason that has been proposed is a sense that we can control risk from other sources, but a nuclear meltdown would be totally outside our control. Perhaps that is the perception, but if you think about it, it really doesn’t make a lot of sense. If there’s a nuclear meltdown, emergency services will report it, and you can evacuate the area. Yes, the radiation moves at the speed of light; but it also dissipates as the inverse square of distance, so if you just move further away you can get a lot safer quite quickly. (Think about the brightness of a lamp in your face versus across a football field. Radiation works the same way.) The damage is also cumulative, so the radiation risk from a meltdown is only going to be serious if you stay close to the reactor for a sustained period of time. Indeed, it’s much easier to avoid nuclear radiation than it is to avoid air pollution; you can’t just stand behind a concrete wall to shield against air pollution, and moving further away isn’t possible if you don’t know where it’s coming from. Control would explain why we fear cars less than airplanes (which is also statistically absurd), but it really can’t explain why nuclear power scares people more than coal and oil.

Another important factor may be an odd sort of bipartisan consensus: While the Left hates nuclear power because it makes corporations profitable or because it’s unnatural and despoils the Earth or something, the Right hates nuclear power because it requires substantial government involvement and might displace their beloved fossil fuels. (The Right’s deep, deep love of the fossil fuel industry now borders on the pathological. Even now that they are obviously economically inefficient and environmentally disastrous, right-wing parties around the world continue to defend enormous subsidies for oil and coal companies. Corruption and regulatory capture could partly explain this, but only partly. Campaign contributions can’t explain why someone would write a book praising how wonderful fossil fuels are and angrily denouncing anyone who would dare criticize them.) So while the two sides may hate each other in general and disagree on most other issues—including of course climate change itself—they can at least agree that nuclear power is bad and must be stopped.

Where do we go from here, then? I’m not entirely sure. As I said, statistical data by itself clearly won’t be enough. We need to find out what it is that makes people so uniquely terrified of nuclear energy, and we need to find a way to assuage those fears.

And we must do this now. For every day we don’t—every day we postpone the transition to a zero-carbon energy grid—is another thousand people dead.

These lines in particular, near the end, finally helped me put it all together:

What is truly revealing is his implication that believing something to be true is the same as it being true. Because if anything, that was the theme of the Republican Convention this week; it was a four-day exercise in emphasizing feelings over facts.

I want you to understand that I am not exaggerating when I say that a Donald Trump Presidency carries a nontrivial risk of triggering global nuclear war. Will this probably happen? No. It has a probability of perhaps 1%. But a 1% chance of a billion deaths is not a risk anyone should be prepared to take.

Donald Trump has essentially no other skills—but he has that one, and it is enough. He knows how to fan the flames of anger and hatred and point them at his chosen targets. He knows how to rally people behind meaningless slogans like “Make America Great Again” and convince them that he has their best interests at heart.

Indeed, Trump’s persuasiveness is one of his many parallels with Adolf Hitler; I am not yet prepared to accuse Donald Trump of seeking genocide, yet at the same time I am not yet willing to put it past him. I don’t think it would take much of a spark at this point to trigger a conflagration of hatred that launches a genocide against Muslims in the United States, and I don’t trust Trump not to light such a spark.

Our enemies are persuasive—and therefore we must be as well. We can no longer act as though facts will automatically convince everyone by the power of pure reason; we must learn to stir emotions and rally crowds just as they do.

Or rather, not just as they do—not quite. When we see lies being so effective, we may be tempted to lie ourselves. When we see people being manipulated against us, we may be tempted to manipulate them in return. But in the long run, we can’t afford to do that. We do need to use reason, because reason is the only way to ensure that the beliefs we instill are true.

Therefore our task must be to make people see reason. Let me be clear: Not demand they see reason. Not hope they see reason. Not lament that they don’t. This will require active investment on our part. We must actually learn to persuade people in such a manner that their minds become more open to reason. This will mean using tools other than reason, but it will also mean treading a very fine line, using irrationality only when rationality is insufficient.

We will be tempted to take the easier, quicker path to the Dark Side, but we must resist. Our goal must be not to make people do what we want them to—but to do what they would want to if they were fully rational and fully informed. We will need rhetoric; we will need oratory; we may even need some manipulation. But as we fight our enemy, we must be vigilant not to become them.

It means demanding fact-checks immediately, not as some kind of extra commentary that happens after the debate, but as something the moderator says right then and there. (You have a staff, right? And they have Google access, right?) When a candidate says something that is blatantly, demonstrably false, they should receive a warning. After three warnings, their mic should be cut for that question. After ten, they should be kicked off the stage for the remainder of the debate. Donald Trump wouldn’t have lasted five minutes. But instead, they not only let him speak, they spent the next week repeating what he said in bold, exciting headlines. At least CNN finally realized that their headlines could actually fact-check Trump’s statements rather than just repeat them.
Above all, we will need to understand why people think the way they do, and learn to speak to them persuasively and truthfully but without elitism or condescension. This is one I know I’m not very good at myself; sometimes I get so frustrated with people who think the Earth is 6,000 years old (over 40% of Americans) or don’t believe in climate change (35% don’t think it is happening at all, another 30% don’t think it’s a big deal) that I come off as personally insulting them—and of course from that point forward they turn off. But irrational beliefs are not proof of defective character, and we must make that clear to ourselves as well as to others. We must not say that people are stupid or bad; but we absolutely must say that they are wrong. We must also remember that despite our best efforts, some amount of reactance will be inevitable; people simply don’t like having their beliefs challenged.

Yet even all this is probably not enough. Many people don’t watch mainstream media, or don’t believe it when they do (not without reason). Many people won’t even engage with friends or family members who challenge their political views, and will defriend or even disown them. We need some means of reaching these people too, and the hardest part may be simply getting them to listen to us in the first place. Perhaps we need more grassroots action—more protest marches, or even activists going door to door like Jehovah’s Witnesses. Perhaps we need to establish new media outlets that will be as widely accessible but held to a higher standard.

One of the great mysteries of astronomy is the Fermi Paradox:Everything we know about astronomy, biology, and probability tells us that there should be, somewhere out in the cosmos, a multitude of extraterrestrial species, and some of them should even be intelligent enough to form civilizations and invent technology. So why haven’t we found any clear evidence of any of them?

Indeed, the Fermi Paradox became even more baffling in just the last two years, as we found literally thousands of new extrasolar planets, many of them quite likely to be habitable. More extrasolar planets have been found since 2014 than in all previous years of human civilization. Perhaps this is less surprising when we remember that no extrasolar planets had ever been confirmed before 1992—but personally I think that just makes it this much more amazing that we are lucky enough to live in such a golden age of astronomy.

The Drake equationwas supposed to tell us how probable it is that we should encounter an alien civilization, but the equation isn’t much use to us because so many of its terms are so wildly uncertain. Maybe we can pin down how many planets there are soon, but we still don’t know what proportion of planets can support life, what proportion of those actually have life, or above all what proportion of ecosystems ever manage to evolve a technological civilization or how long such a civilization is likely to last. All possibilities from “they’re everywhere but we just don’t notice or they actively hide from us” to “we are actually the only ones in the last million years” remain on the table.

But let’s suppose that aliens do exist, and indeed have technology sufficient to reach our solar system. Faster-than-light capability would certainly do it, but it isn’t strictly necessary; with long lifespans, cryonic hibernation, or relativistic propulsion aliens could reasonably expect to travel at least between nearby stars within their lifetimes. The Independence Day aliens appear to have FTL travel, but interestingly it makes the most sense if they do not have FTL communication—it took them 20 years to get the distress call because it was sent at lightspeed. (Or perhaps the ansible was damaged in the war, and they fell back to a lightspeed emergency system?) Otherwise I don’t quite get why it would take the Queen 20 years to deploy her personal battlecruiser after the expeditionary force she sent was destroyed—maybe she was just too busy elsewhere to bother with our backwater planet? What did she want from our planet again?

That brings me to my next point: Just what motivation would aliens have for attacking us? We often take it for granted that if aliens exist, and have the capability to attack us, they would do so. But that really doesn’t make much sense. Do they just enjoy bombarding primitive planets? I guess it’s possible they’re all sadistic psychopaths, but it seems like any civilization stable enough to invent interstellar travel has got to have some kind of ethical norms. Maybe they see us as savages or even animals, and are therefore willing to kill us—but that still means they need a reason.

Another idea, taken seriously in Vand less so in Cowboys & Aliens, is that there is some sort of resource we have that they want, and they’re willing to kill us to get it. This is probably such a common trope because it has been a common part of human existence; we are very familiar with people killing other people in order to secure natural resources such as gold, spices, or oil. (Indeed, to some extent it continues to this day.)

But this actually doesn’t make a lot of sense on an interstellar scale. Certainly water (V) and gold(Cowboys & Aliens) are not things they would have even the slightest reason to try to claim from an inhabited planet, as comets are a better source of water and asteroids are a better source of gold. Indeed, almost nothing inorganic could really be cost-effective to obtain from an inhabited planet; far easier to just grab it from somewhere that won’t fight back, and may even have richer veins and lower gravity.

It’s possible they would want something organic—lumber or spices, I guess. But I’m not sure why they’d want those things, and it seems kind of baffling that they wouldn’t just trade if they really want them. I’m sure we’d gladly give up a great deal of oregano and white pine in exchange for nanotechnology and FTL. I guess I could see this happening because they assume we’re too stupid to be worth trading with, or they can’t establish reliable means of communication. But one of the reasons why globalization has succeeded where colonialism failed is that trade is a lot more efficient than theft, and I find it unlikely that aliens this advanced would have failed to learn that lesson.

Media that imagines they’d enslave us makes even less sense; slavery is wildly inefficient, and they probably have such ludicrously high productivity that they are already coping with a massive labor glut. (I suppose maybe they send off unemployed youths to go conquer random planets just to give them something to do with their time? Helps with overpopulation too.)

I actually thought Independence Day: Resurgence did a fairlygood job of finding a resource that is scarce enough to be worth fighting over while also not being something we would willingly trade. Spoiler alert, I suppose:

Molten cores. Now, I haven’t the foggiest what one does with molten planet cores that somehow justifies the expenditure of all that energy flying between solar systems and digging halfway through planets with gigantic plasma drills, but hey, maybe they are actually tremendously useful somehow. They certainly do contain huge amounts of energy, provided you can extract it efficiently. Moreover, they are scarce; of planets we know about, most of them do not have molten cores. Earth, Venus, and Mercury do, and we think Mars once did; but none of the gas giants do, and even if they did, it’s quite plausible that the Queen’s planet-cracker drill just can’t drill that far down. Venus sounds like a nightmare to drill, so really the only planet I’d expect them to extract before Earth would be Mercury. And maybe they figured they needed both cores to justify the trip, in which case it would make sense to hit the inhabited planet first so we don’t have time to react and prepare our defenses. (I can’t imagine we’d take giant alien ships showing up and draining Mercury’s core lying down.) I’m imagining the alien economist right now, working out the cost-benefit analysis of dealing with Venus’s superheated atmosphere and sulfuric acid clouds compared to the cost of winning a war against primitive indigenous apes with nuclear missiles: Well, doubling our shield capacity is cheaper than covering the whole ship in sufficient anticorrosive, so I guess we’ll go hit the ape planet. (They established in the first film that their shields can withstand direct hits from nukes—the aliens came prepared.)

So, maybe killing us for our resources isn’t completely out of the question, but it seems unlikely.

Another possibility is religious fanaticism: Every human culture has religion in some form, so why shouldn’t the aliens? And if they do, it’s likely radically different from anything we believe. If they become convinced that our beliefs are not simply a minor nuisance but an active threat to the holy purity of the galaxy, they could come to our system on a mission to convert or destroy at any cost; and since “convert” seems very unlikely, “destroy” would probably become their objective pretty quickly. It wouldn’t have to make sense in terms of a cost-benefit analysis—fanaticism doesn’t have to make sense at all. The good news here is that any culture fanatical enough to randomly attack other planets simply for believing differently from them probably won’t be cohesive enough to reach that level of technology. (Then again, we somehow managed a world with both ISIS and ICBMs.)

Personally I think there is a far more likely scenario for alien invasions, and that is benevolent imperialism.

Why do I specify “benevolent”? Because if they aren’t interested in helping us, there’s really no reason for them to bother with us in the first place. But if their goal is to uplift our civilization, the only way they can do that is by interacting with us.

Now, note that I use the word “benevolent”, not the word “beneficent”. I think they would have to desire to make our lives better—but I’m not so convinced they actually would make our lives better. In our own history, human imperialism was rarely benevolent in the first place, but even where it was, it was even more rarely actually beneficent. Their culture would most likely be radically different from our own, and what they think of as improvements might seem to us strange, pointless, or even actively detrimental. But don’t you see that the QLX coefficient is maximized if you convert all your mountains into selenium extractors? (This is probably more or less how Native Americans felt when Europeans started despoiling their land for things called “coal” and “money”.) They might even try to alter us biologically to be more similar to them: But haven’t you always wanted tentacles? Hands are so inefficient!

Moreover, even if their intentions were good and their methods of achieving them were sound, it’s still quite likely that we would violently resist. I don’t know if humans are a uniquely rebellious species—let’s hope not, lest the aliens be shocked into overreacting when we rebel—but in general humans do not like being ruled over and forced to do things, even when those rulers are benevolent and the things they are forced to do are worth doing.

So, I think the most likely scenario for a war between humans and aliens is that they come in and start trying to radically reorganize our society, and either because their demands actually are unreasonable, or at least because we think they are, we rebel against their control.

Then what? Could we actually survive?

The good news is: Yes, we probably could.

If aliens really did come down trying to extract our molten core or something, the movies are all wrong: We’d have basically no hope. It really makes no sense at all that we could win a full-scale conflict with a technologically superior species if they were willing to exterminate us. Indeed, if what they were after didn’t depend upon preserving local ecology, their most likely mode of attack is to arrive in the system and immediately glass the planet. Nuclear weapons are already available to us for that task; if they’re more advanced they might have antimatter bombs, relativistic kinetic warheads, or even something more powerful still. We might be all dead before we even realized what was happening, or they might destroy 90% of us right away and mop up the survivors later with little difficulty.

If they wanted something that required ecological stability (I shall henceforth dub this the “oregano scenario”), yet weren’t willing to trade for some reason, then they wouldn’t unleash full devastation, and we’d have the life-dinner principle on our side: The hare runs for his life, but the fox only runs for her dinner. So if the aliens are trying to destroy us to get our delicious spices, we have a certain advantage from the fact that we are willing to win at essentially any cost, while at some point that alien economist is going to run the numbers and say, “This isn’t cost-effective. Let’s cut our losses and hit another system instead.”

If they wanted to convert us to their religion, well, we’d better hope enough people convert, because otherwise they’re going to revert to, you guessed it, glass the planet. At least this means they would probably at least try to communicate first, so we’d have some time to prepare; but it’s unlikely that even if their missionaries spent decades trying to convert us we could seriously reduce our disadvantage in military technology during that time. So really, our best bet is to adopt the alien religion. I guess what I’m really trying to say here is “All Hail Xemu.”

But in the most likely scenario that their goal is actually to make our lives better, or at least better as they see it, they will not be willing to utilize their full military capability against us. They might use some lethal force, especially if they haven’t found reliable means of nonlethal force on sufficient scale; but they aren’t going to try to slaughter us outright. Maybe they kill a few dissenters to set an example, or fire into a crowd to disperse a riot. But they are unlikely to level a city, and they certainly wouldn’t glass the entire planet.

Our best bet would probably actually be nonviolent resistance, as this has a much better track record against benevolent imperialism. Gandhi probably couldn’t have won a war against Britain, but he achieved India’s independence because he was smart enough to fight on the front of public opinion. Likewise, even with one tentacle tied behind their backs by their benevolence, the aliens would still probably be able to win any full-scale direct conflict; but if our nonviolent resistance grew strong enough, they might finally take the hint and realize we don’t want their so-called “help”.

So, how about someone makes that movie? Aliens come to our planet, not to kill us, but to change us, make us “better” according to their standards. QLX coefficients are maximized, and an intrepid few even get their tentacles installed. But the Resistance arises, and splits into two factions: One tries to use violence, and is rapidly crushed by overwhelming firepower, while the other uses nonviolent resistance. Ultimately the Resistance grows strong enough to overthrow the alien provisional government, and they decide to cut their losses and leave our planet. Then, decades later, we go back to normal, and wonder if we made the right decision, or if maybe QLX coefficients really were the most important thing after all.

Their stated goal in life is to save humanity from destruction. And when you put it that way, it sounds pretty darn important. How can you disagree with wanting to save humanity from destruction?

Well, there are actually people who do (the Voluntary Human Extinction movement), but they are profoundly silly. It should be obvious to anyone with even a basic moral compass that saving humanity from destruction is a good thing.

It’s not the goal of fighting existential risk that bothers me. It’s the approach. Specifically, they almost all seem to focus on exotic existential risks, vivid and compelling existential risks that are the stuff of great science fiction stories. In particular, they have a rather odd obsession with AI.

Maybe it’s the overlap with Singularitarians, and their inability to understand that exponentials are not arbitrarily fast; if you just keep projecting the growth in computing power as growing forever, surely eventually we’ll have a computer powerful enough to solve all the world’s problems, right? Well, yeah, I guess… if we can actually maintain the progress that long, which we almost certainly can’t, and if the problems turn out to be computationally tractable at all (the fastest possible computer that could fit inside the observable universe could not brute-force solve the game of Go, though a heuristic AI did just beat one of the world’s best players), and/or if we find really good heuristic methods of narrowing down the solution space… but that’s an awful lot of “if”s.

There is one thing that we really need to worry about destroying humanity, and one other thing that could potentially get close over a much longer timescale. The long-range threat is ecological collapse; as global climate change gets worse and the oceans become more acidic and the aquifers are drained, we could eventually reach the point where humanity cannot survive on Earth, or at least where our population collapses so severely that civilization as we know it is destroyed. This might not seem like such a threat, since we would see this coming decades or centuries in advance—but we are seeing it coming decades or centuries in advance, and yet we can’t seem to get the world’s policymakers to wake up and do something about it. So that’s clearly the second-most important existential risk.

But the most important existential risk, by far, no question, is nuclear weapons.

Nuclear weapons are the only foreseeable, preventable means by which humanity could be destroyed in the next twenty minutes.

I’ve intentionally linked the Union of Concerned Scientists as one of those sources. Now they are people who understand existential risk. They don’t talk about AI and asteroids and aliens (how alliterative). They talk about climate change and nuclear weapons.

We must stop this. We must get rid of these weapons. Next to that, literally nothing else matters.

“What if we’re conquered by tyrants?” It won’t matter. “What if there is a genocide?” It won’t matter. “What if there is a global economic collapse?” None of these things will matter, if the human race wipes itself out with nuclear weapons.

To speak like an economist for a moment, the utility of a global nuclear war must be set at negative infinity. Any detectable reduction in the probability of that event must be considered worth paying any cost to achieve. I don’t care if it costs $20 trillion and results in us being taken over by genocidal fascists—we are talking about the destruction of humanity. We can spend $20 trillion (actually the US as a whole does every 14 months!). We can survive genocidal fascists. We cannot survive nuclear war.

The good news is, we shouldn’t actually have to pay that sort of cost. All we have to do is dismantle our nuclear arsenal, and get other countries—particularly Russia—to dismantle theirs. In the long run, we will increase our wealth as our efforts are no longer wasted maintaining doomsday machines.

The thinking, anyway, is that this is basically a Prisoner’s Dilemma. If the US disarms and Russia doesn’t, Russia can destroy the US. Conversely, if Russia disarms and the US doesn’t, the US can destroy Russia. If neither disarms, we’re left where we are. Whether or not the other country disarms, you’re always better off not disarming. So neither country disarms.

But I contend that it is not, in fact, a Prisoner’s Dilemma. It could be a Stag Hunt; if that’s the case, then only multilateral disarmament makes sense, because the best outcome is if we both disarm, but the worst outcome is if we disarm and they don’t. Once we expect them to disarm, we have no temptation to renege on the deal ourselves; but if we think there’s a good chance they won’t, we might not want to either. Stag Hunts have two stable Nash equilibria; one is where both arm, the other where both disarm.

But in fact, I think it may be simply the trivial game.

There aren’t actually that many possible symmetric two-player nonzero-sum games (basically it’s a question of ordering 4 possibilities, and it’s symmetric, so 12 possible games), and one that we never talk about (because it’s sort of boring) is the trivial game: If I do the right thing and you do the right thing, we’re both better off. If you do the wrong thing and I do the right thing, I’m better off. If we both do the wrong thing, we’re both worse off. So, obviously, we both do the right thing, because we’d be idiots not to. Formally, we say that cooperation is a strictly dominant strategy. There’s no dilemma, no paradox; the self-interested strategy is the optimal strategy. (I find it kind of amusing that laissez-faire economics basically amounts to assuming that all real-world games are the trivial game.)

That is, I don’t think the US would actually benefit from nuking Russia, even if we could do so without retaliation. Likewise, I don’t think Russia would actually benefit from nuking the US. One of the things we’ve discovered—the hardest way possible—through human history is that working together is often better for everyone than fighting. Russia could nuke NATO, and thereby destroy all of their largest trading partners, or they could continue trading with us. Even if they are despicable psychopaths who think nothing of committing mass murder (Putin might be, but surely there are people under his command who aren’t?), it’s simply not in Russia’s best interest to nuke the US and Europe. Likewise, it is not in our best interest to nuke them.

So I say, let’s stop playing. Yes, let’s unilaterally disarm, the thing that so many policy analysts are terrified of because they’re so convinced we’re in a Prisoner’s Dilemma or a Stag Hunt. “What’s to stop them from destroying us, if we make it impossible for us to destroy them!?” I dunno, maybe basic human decency, or failing that, rationality?

Several other countries have already done this—South Africa unilaterally disarmed, and nobody nuked them. Japan refused to build nuclear weapons in the first place—and I think it says something that they’re the only people to ever have them used against them.

Our conventional military is plenty large enough to defend us against all realistic threats, and could even be repurposed to defend against nuclear threats as well, by a method I call credible targeted conventional response. Instead of building ever-larger nuclear arsenals to threaten devastation in the world’s most terrifying penis-measuring contest, you deploy covert operatives (perhaps Navy SEALS in submarines, or double agents, or these days even stealth drones) around the world, with the standing order that if they have reason to believe a country initiated a nuclear attack, they will stop at nothing to hunt down and kill the specific people responsible for that attack. Not the country they came from; not the city they live in; those specific people. If a leader is enough of a psychopath to be willing to kill 300 million people in another country, he’s probably enough of a psychopath to be willing to lose 150 million people in his own country. He likely has a secret underground bunker that would allow him to survive, at least if humanity as a whole does. So you should be threatening the one thing he does care about—himself. You make sure he knows that if he pushes that button, you’ll find that bunker, drop in from helicopters, and shoot him in the face.

The “targeted conventional response” should be clear by now—you use non-nuclear means to respond, and you target the particular leaders responsible—but let me say a bit more about the “credible” part. The threat of mutually-assured destruction is actually not a credible one. It’s not what we call in game theory a subgame perfect Nash equilibrium. If you know that Russia has launched 1500 ICBMs to destroy every city in America, you actually have no reason at all to retaliate with your own 1500 ICBMs, and the most important reason imaginable not to. Your people are dead either way; you can’t save them. You lose. The only question now is whether you risk taking the rest of humanity down with you. If you have even the most basic human decency, you will not push that button. You will not “retaliate” in useless vengeance that could wipe out human civilization. Thus, your threat is a bluff—it is not credible.

But if your response is targeted and conventional, it suddenly becomes credible. It’s exactly reversed; you now have every reason to retaliate, and no reason not to. Your covert operation teams aren’t being asked to destroy humanity; they’re being tasked with finding and executing the greatest mass murderer in history. They don’t have some horrific moral dilemma to resolve; they have the opportunity to become the world’s greatest heroes. Indeed, they’d very likely have the whole world (or what’s left of it) on their side; even the population of the attacking country would rise up in revolt and the double agents could use the revolt as cover. Now you have no reason to even hesitate; your threat is completely credible. The only question is whether you can actually pull it off, and if we committed the full resources of the United States military to preparing for this possibility, I see no reason to doubt that we could. If a US President can be assassinated by a lone maniac (and yes, that is actually what happened), then the world’s finest covert operations teams can assassinate whatever leader pushed that button.

This is a policy that works both unilaterally and multilaterally. We could even assemble an international coalition—perhaps make the UN “peacekeepers” put their money where their mouth is and train the finest special operatives in the history of the world tasked with actually keeping the peace.

Let’s not wait for someone else to save humanity from destruction. Let’s be the first.